Patent GB-847664-A (GB)
Title: Improvements relating to synthetic lubricants
IPC: C10M169/00
Filed: 1957-05-24
Abstract: A lubricating composition comprises a blend of a liquid aliphatic diester of a saturated aliphatic dicarboxylic acid and a polyester soluble in the diester and having the general formula : <FORM:0847664/IV(a)/1> where n is an integer, the R6s are methyl or ethyl groups, the R7s are alkyl groups having 1-4 carbon atoms, and the R1s are alkylene groups having 4-14 carbon atoms, the relative proportions of diester and polyester in the blend being such that the viscosity of the blend at 210 DEG  F is 4-30 centistokes.  The diester preferably has the formula R4OOCR5COOR4 where R5 is an alkylene group having 4-14 carbon atoms and the R4s are alkyl groups, especially branchedchain, having 4-18 carbon atoms.  Examples of suitable diesters are (i) di(2-ethylhexyl) sebacate, (ii) di (3,5,5-trimethylhexyl) sebacate, (iii) 2-ethylhexyl (3,5,5-trimethylhexyl) sebacate and mixtures of (i), (ii) and (iii). The lubricating composition may contain an antioxidant such as phenothiazine, or a crystallization suppressant such as a polymerized alkyl ester of acrylic or methacrylic acid.  In the examples, lubricating compositions are described consisting of diester (a blend of octyl nonyl sebacate, dioctyl sebacate and dinonyl sebacate, prepared by reacting together sebacic acid, 2-ethylhexanol and 3,5,5-trimethylhexanol), polyester (prepared by reacting together 2,2-dimethyl-1,3-propanediol with sebacic acid, commercial isosebacic acid or an equimolecular mixture of sebacic acid, and 1,1,3-and 1,3,3-trimethyladipic acids, or by reacting together 2-methyl-2-propyl-1,3-propanediol with sebacic acid) and phenothiazine.  The commercial isosebacic acid is stated to consist essentially of 1-ethyl suberic acid, 1,4-diethyl adipic acid and sebacic acid.  Specification 763,077 is referred to.ALSO:A polyester, which is employed as an ingredient of a lubricating composition (see Group III), has the formula:  HO [CH2C(R6) (R7) CH2OOCR1COO]n CH2 C(R6) (R7) CH2OH where n is an integer, the R6s are methyl or ethyl groups, the R7s are alkyl groups having 1-4 carbon atoms and the R1s are alkylene groups having 4-14 carbon atoms.  In examples, polyesters are prepared by reacting together 2, 2-dimethyl-1,3-propanediol with sebacic acid, commercial isosebacic acid or an equimolecular mixture of sebacic acid and 1, 1, 3- and 1, 3, 3-trimethyl-adipic acids.  The commercial isosebacic acid is stated to consist essentially of 1-ethyl-suberic acid, 1, 4-diethyl-adipic acid and sebacic acid. Specification 763,077 is referred to.ALSO:A lubricating composition, suitable for the lubrication of aero gas turbines, comprises a blend of a liquid aliphatic diester of a saturated aliphatic dicarboxylic acid and a polyester soluble in the diester and having the general formula HO[CH2C(R6)(R7)CH2OOCR1 COO]nCH2C(R6)(R7)CH2OH where n is an integer, the R6s are methyl or ethyl groups, the R7s are alkyl groups having 1-4 carbon atoms, and the R1s are alkylene groups having 4-14 carbon atoms, the relative proportions of diester and polyester in the blend being such that the viscosity of the blend at 210 DEG F. is 4-30 centistokes.  The diester preferably has the formula R4OOCR5COOR4 where R5 is an alkylene group having 4-14 carbon atoms and the R4s are alkyl groups, especially branched-chain, having 4-18 carbon atoms.  Examples of suitable diesters are (i) di(2-ethylhexyl) sebacate, (ii) di(3,5,5-trimethylhexyl) sebacate, (iii) 2-ethylhexyl (3,5,5-trimethylhexyl) sebacate and mixtures of (i), (ii) and (iii). The lubricating composition may contain an antioxidant such as phenothiazine, or a crystallization suppressant such as a polymerized alkyl ester of acrylic or methacrylic acid.  In the examples, lubricating compositions are described consisting of diester (a blend of octyl nonyl sebacate, dioctyl sebacate and dinonyl sebacate, prepared by reacting together sebacic acid, 2-ethylhexanol and 3,5,5-trimethylhexanol), polyester (prepared by reacting together 2,2-dimethyl-1,3-propanediol with sebacic acid, commercial isosebacic acid or an equimolecular mixture of sebacic acid and 1,1,3-and 1,3,3 - trimethyl - adipic acids, or by reacting together 2-methyl-2-propyl-1,3-propanediol with sebacic acid) and phenothiazine.  The commercial isosebacic acid is stated to consist essentially of 1-ethyl subecic acid, 1,4-diethyladipic acid and sebacic acid.  For comparison purposes, a similar lubricating composition is described wherein the polyester is poly (propylene glycol sebacate).  Specification 763,077 is referred to.